Track chisel



July 7, 1925.

E. WOODINGS ET AL TRACK CHISEL Filed April 0v new 701m Patented July 7, 1925.

unites stares.

EMANUEL woonrncs, or cannons,

svnvanrn, Ass enons 'ro nun WILLIAM J. cos'rnpizo, or vnnona, rennwocnrnes rouse & moon oonrenv, or VERONA,

rnnusrnvanrn, A eonroeermn or rnunsrtveure.

reac s cnIsEL.

Application filed April To all whom it may concern:

Be it known that EMANUEL mmune and WILLIAM J. COSTELLO, residing at Oakmont and Verona, respectively, in the county of Allegheny and State of Pennsylvania, citizens of the United States, have invented 0r discovered certain new and useful Improvements in Track Chisels, of whichimprovementthe following is a specification.

Theinvention, relates to track chisels, these being combined cutting and hammering tools used by trackmen, and which are attached towooden handles in a manner similar: to carpenters. hammers.

-As customarily formed, a track chisel has a hammer head at one end which is sufli ciently hardened to prevent its mushrooming when used for driving or when struck to cause the chisel to cut,,and at the other end of the tool. there is aiwedge-shaped chisel having a straight cutting edge, the end of the chisel being hardened to retain its cutting edge. -The intermediate portion of the tool is sutliciently soft to prevent breaks age by the impact to which it is subjected.

Inthe manufacture of these prior'track chisels .only a small portion of the end of the chisel portionof the tool is hardened to form a cutting edge, and in fact only a small portion may be. so hardened because/the entire chisel shank is wedge-shaped and therefore cannot beuniformlyhardened for any substantial distance from its cutting edge. Thev result of this is that when a chiselwears or is ground downbut a small distance, it must be reheated, reshaped and then re-heattreated to produce a sufficiently hardened end to retain a cutting edge. This not only involves .much time and expense, but, be cause the blacksmiths who do it are ordinarily not as skilled in heat treatment as are the manufacturers of the chisels, and because they donot ordinarily-have adequate facilities for heat treating, the reshaped and reheat-treated chisels are frequently not as satisfactory as those produced by the manufacturers.

The object of this invention is to provide a track chisel having a chisel shank so shaped and so hardened that it may be used and reground indefinitely without reheating and reshaping the shank and then hardening it by heat treatment; and a chisel so characterized which is also strong and durable,

7, 1825. Serial No. 21,370.

and which has its cutting edge shaped for increased effectiveness.

In the drawings, Fig. 1 is a perspective view of a track chisel embodying the invention; Fig. 2 a side View of the chisel of Fig. 1; Fig. 3 a transverse sectional view of the chisel shank, the plane of view being indicated by the line HIIII, Fig. 2; Fig. 4 a view corresponding to Fig. 3 illustrating a modification in the shape of the chisel shank; and Fig. 5 a diagrammatic view illustrating one manner of using the track chisel.

According to this invention, a track chisel is provided with a chisel-forming shank of substantially uniform cross-sectional area,

and such shank isuniformly hardened for a material distance from its outer end so that the cutting edge of the chisel may from time to time be resharpened by merely grinding it, andwithout reheating. reshaping and rehardening the shank. The provision of a chiseleforming shank of uniform cross-sectional area no'tonly affords a structure which is capable of being uniformly hardened for a material distance from its outer end. but also a structure which may be reground indefinitely without changing the shape and extent of the. cutting edge.

Having reference to the illustrative embodiment of the invention, the chisel comprises a hammer head 1 which is sut'ficiently hardened by proper heat treatment to prevent its becoming mushroomed when used for driving. or when struck to cause the chisel to cut, an intermediate section 2 provided with a handle-receiving opening 3 and which is sufiicientlysoft to prevent breakage by the impact to which the chisel is subjected, and a chisel shank 4' which is of sub.- stantially uniform cross-sectional area. Preferably the chisel shank is diamondshaped in cross-se ction, as illustrated in 3, having major axes AA and B-B, the plane of the cutting edge 5 of the chisel lying in the major axis A-A. lVhen the shank is so constructed, it has a plane of maximum thickness transverse to the center of the cutting edge 5, and its thickness gradually diminishes outwardly on both sides of this medial plane. .Thus the cutting edge is strengthened and reen'forced to the maximum extent at its center where it is subjected to greatest strain. While the chisel shank is preferably diamond-shaped in cross-section, it may be otherwise shaped to have the same, or substantially the same, advantages which have been explained with reference to the diamond-shaped shank, as for example it may be of the general elliptical cross-sectional shape illustrated in Fig.

Preferably, the cutting edge 5 is rounded, .as particularly illustrated in Fig. 5, so that the chisel may be more effectively used to nick rails 7 for cutting them, it being understood that when the rails are so nicked it is desirable to place nicks in the concavities between the web of a rail and its head and base in the general manner illustrated in Fig. 5.

The track chisel may be formed of various suitable alloy steels, or it may be formed of a plain carbon steel, being low in sulphur and having a carbon content of from about .75% to .90%. Preferably it is formed of plain high carbon steel substantially as de-. scribed because of its comparative ease of heat treatment. After a chisel has been forged, it may be variously heat treated, de pending largely upon the particular steel of which it is made, to give it the physical characteristics previously explained. By way of example, and not of limitation, a chisel formed of a plain high carbon steel of the approximate carbon content stated may be first heated to a temperature of from about 1400 to 1450 F., and its hammer head end then quenched in oil to about the handle opening 3 until it reaches a temperature of from about 300 F. to 400 F. This results in giving the head a hard texture which is nevertheless sufficiently tough to resist breakage. Afterwards the chisel shank 4: is heated to about 1200 F., that is to say about a cherry red heat, and is quenched in water for about ten seconds. If it is desired to uniformly harden the end of the shank 4 for a distance of about three inches from its outer end, the color of the shank is observed after it has been removed from the quenching water until a pigeon-blue color, which starts at the back of the shank, reaches a point which is about three inches from the outer end of the shank. Thereafter the shank is quenched cold, which results in its becoming uniformly hardened and capable of retaining a cutting edge throughout the hardened portion as the end of the shank is ground down for sharpening.

In the use of the chisel it may be reground indefinitely without reshaping the chisel shank, which necessarily means reheating the shank and re-heat-treating it. This not only eliminates a very substantial item of expense in connection with the use of such chisels, but, by providing a chisel having a shank of substantially uniform cross-sectional area which is uniformly hardened for a material distance from its end, and which hardening is effected by the manufacturer with his ample facilities for properly doing it, there is eliminated the liability of improper or insufficient rehardening incident to the prior forms of chisels.

According to the provisions of the patent statutes, we have explained the principle and operation of our invention, and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced by other forms of track chisels than that specifically illustrated and described.

We claim as our invention:

1. A track chisel having a chisel forming shank of substantially uniform cross sectional area terminating with a cutting edge and gradually diminishing in thickness outwardly on both sides of its medial lane transverse to said cutting edge, said siank being uniformly hardened for a material distance from its end, whereby the ed e of the chisel may be reground indefinitely to produce a hardened cutting edge without reshaping and rehardening said shank.

2. A track chisel having a chisel-forming diamond-shaped shank of substantially uniform cross-sectional area terminating with a cutting edge lying in the plane of a major axis of the shank, said shank being uniformly hardened for a material distance from its end, whereby the edge of the chisel may be reground indefinitely to produce a harened cutting edge without reshaping and rehardening said shank.

In testimony whereof, we have hereunto set our hands.

EMANUEL WOODINGS. WILLIAM J. COSTELLO. 

